The invention concerns a conveyor for packages, and, more particularly, a conveyor for form flexible packages such as newspapers, textiles or sacks.
In international patent application WO 94/04850, filed Aug. 16, 1993 and published Mar. 3, 1994, a roller conveyor is disclosed for flexible packages of, for example, washcloths. The roller conveyor essentially consists of numerous parallel, sequential rollers that form an essentially horizontal transport surface for the packages. In order to prevent the flexible packages from falling through, or being drawn through, the spaced, sequential rollers, several narrow, continuously circulating belts are guided around groups of sequential rollers. The gaps between the rollers are hence substantially closed by a network of belts.
The narrow belts are guided by a plurality of double-conical sections positioned along the otherwise cylindrical rollers, thereby remaining parallel and evenly distributed on the rollers. A plurality of conical sections corresponding to the number of belts are distributed along the length of each roller with cylindrical sections therebetween. Because the narrow belts tend to creep up the rising conical surfaces of the double-conical sections, the belts become centered by the opposing rising conical surfaces at the highest point of the adjacent conical surfaces. Therefore, each belt is centered on a plurality of double-conical sections correspondingly positioned along a group of sequential rollers. The cylindrical sections of the rollers between the double-conical sections have a width that is greater than the width of the belts, while the width of the double-conical sections approximately corresponds to the width of the belt.
With this roller conveyor, the belts can be pressed downwardly (especially by the packages) and diverted from the double-conical section toward the cylindrical section. Because the cylindrical section is wider than the belt, the belt is allowed to be further diverted until it fully rests on the cylindrical sections between neighboring conical sections, and remains there, where it does not effectively support the packages. A shoulder between the cylindrical and double-conical sections further prevents the belt from independently creeping back onto the double-conical section. Therefore, in order to properly realign the belts, they must be manually adjusted while the conveyor is running.